Conventionally, image processing apparatuses such as display apparatuses, image capturing apparatuses, image coding apparatuses, and image decoding apparatuses process pictures per unit known as pixels. Each pixel has three individual sub-pixels, named green, red, and blue (RGB). Display apparatuses control the intensity of each sub-pixel to mix an overall color for that pixel. There are various levels of intensity of each sub-pixel. The level variation depends on the bit-depth.
A bit-depth indicates an information capacity per pixel, and is specifically the number of bits per sub-pixel. For instance, when the bit-depth is 8 bits, the intensity of each sub-pixel can be expressed in 256 (2 to the 8th power) levels. When the bit-depth is 10 bits, the intensity of each sub-pixel can be expressed in 1024 (2 to the 10th power) levels.
Furthermore, when the bit-depth is 8 bits, the number of combinations of the intensity levels of three sub-pixels within a single pixel is 256 to the power of 3 (16,777,216). When the bit-depth is 10 bits, the number of combinations of the intensity levels of three sub-pixels within a single pixel is 1024 to the power of 3 (1,073,741,824). This means that when the bit-depth is 10 bits, the number of reproducible colors is 64 times greater than that for the bit-depth of 8 bits.
In recent years, professional display apparatuses can display a picture having a bit-depth of 12 bits or 16 bits. Even consumer display apparatuses can display a picture having a bit-depth higher than 8 bits in some cases.
Display apparatuses capable of reproducing a larger number of colors enable smoother transitions from color to color and display of more lifelike colors. That is to say, a higher bit-depth enables smoother transitions from color to color and display of more lifelike colors. Therefore, rather than display of pictures having a bit-depth of 8 bits, consumers prefer display of pictures having a higher bit-depth.
Note that a picture displayed with a bit-depth of 8 bits is called an 8-bit picture. Likewise, a picture displayed with a bit-depth of 10 bits is called a 10-bit picture. That is to say, a picture displayed with a bit-depth of n bits is generally referred to as an n-bit picture.
Here, in order to output a picture having a higher bit-depth, a plurality of massively available 8-bit video processors may be used.